Preparation, Crystal Structure and Fungicidal Activity of N-(5-(benzofuranol-7-oxymethyl)-1,3,4-thiadiazol-2-yl)amide Compounds

A variety of new N-(5-(benzofuranol-7-oxymethyl)-1,3,4-thiadiazol-2-yl)amide compounds (8a-i) were synthesized through four steps from benzofuranol as raw materials. The crystal structure of compound 8a(C17H21N3O3S, Mr=347.43) was measured by X-ray diffraction, which was classified as monoclinic system, Z= 4, V =1742.72(8) Å3, Dc=1.324 Mg/m3, F(000) = 736, S =1.03, µ = 0.21 mm−1, space group P21with a =9.9177(3), b =8.9519(2), c =19.8679(5) Å, the final R =0.035 and wR =0.105 for 3873 observed reflections (I> 2σ(I)).The X-ray structure presented N(3)–H(3)···N(2) and C(6)–H(6)···O(3) intermolecular hydrogen bonds, which acted as an important role in stabilizing the crystal structure. Additionally, preliminary biological assay on compound 8ashowed good fungicidal activity in vivo,with the inhibition of 75% against Pseudoperonospora cubensisat 200 mg/L.